CVE-2026-24785: Clatter has a PSK Validity Rule Violation issue

Protocol compliance vulnerability. The library allowed post-quantum handshake patterns that violated the PSK validity rule (Noise Protocol Framework Section 9.3). This could allow PSK-derived keys to be used for encryption without proper randomization by self-chosen ephemeral randomness, weakening security guarantees and potentially allowing catastrophic key reuse.

Affected default patterns include noise_pqkk_psk0, noise_pqkn_psk0, noise_pqnk_psk0, noise_pqnn_psk0, and some hybrid variants. Users of these patterns may have been using handshakes that do not meet the intended security properties.